Controversy in statistical analysis of functional magnetic resonance imaging data

To test the validity of statistical methods for fMRI data analysis, Eklund et al. (1) used, for the first time, large-scale experimental data rather than simulated data. Using resting-state fMRI measurements to represent a null hypothesis of no task-induced activation, the authors compare familywise error rates for voxel-based and cluster-based inferences for both parametric and nonparametric methods. Eklund et al.’s study used three fMRI statistical analysis packages. They found that, for a target familywise error rate of 5%, the parametric methods gave invalid cluster-based inferences and conservative voxel-based inferences

Vibration perception thresholds in the finger pulp of little finger at different frequencies in 269 healthy girls and boys.

<p>Values, expressed in dB (relative to 10^-6 m/s²⁾, are means and 95% confidence intervals in parenthesis.</p><p>Vibration perception thresholds in the finger pulp of little finger at different frequencies in 269 healthy girls and boys.</p

Vibration perception thresholds in the finger pulp of index finger at different frequencies in 269 healthy girls and boys.

<p>Values, expressed in dB (relative to 10^-6 m/s²⁾, are means and 95% confidence intervals in parenthesis.</p><p>Vibration perception thresholds in the finger pulp of index finger at different frequencies in 269 healthy girls and boys.</p

Photo showing the experimental set-up.

<p>The subject is sitting with the arm/hand and leg/foot, respectively in a relaxed position (A). The investigated skin area (index or little finger, head or the first or fifth metatarsal bone or heel) is placed on a vibrating probe (insert). The subject regulates the intensity of the vibration by pressure a button on a remote control (arrow) in his/her contralateral hand (B). The result is a tactilogram (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119753#pone.0119753.g002" target="_blank">Fig. 2</a>). The probe for the foot is shown in (C) and the green light (D) indicates that the pressure is appropriate on the investigated area. The person on the photo is <i>not</i> one of the subjects in the study.</p

Height and weight of the 269 healthy children included in the study.

<p>Values are means and 95% confidence intervals in parenthesis.</p><p>^a Data missing in two subjects.</p><p>Height and weight of the 269 healthy children included in the study.</p

Spaghetti plots with vibration perception thresholds.

<p>Vibration perception thresholds at different frequencies from the index fingers in young (8–10 years) and older (16–20 years) children in girls (A) and boys (B). Values, expressed in dB (relative to 10^-6 m/s²), are means and 95% confidence intervals.</p

Vibration perception thresholds at the fifth metatarsal in the sole of the foot at different frequencies in 269 healthy girls and boys.

<p>Values, expressed in dB (relative to 10^-6 m/s²⁾, are means and 95% confidence intervals in parenthesis.</p><p>Vibration perception thresholds at the fifth metatarsal in the sole of the foot at different frequencies in 269 healthy girls and boys.</p

Vibration perception thresholds at the heel in the sole of the foot at different frequencies in 269 healthy girls and boys.

<p>Values, expressed in dB (relative to 10^-6 m/s²⁾, are means and 95% confidence intervals in parenthesis.</p><p>Vibration perception thresholds at the heel in the sole of the foot at different frequencies in 269 healthy girls and boys.</p

Flow chart of study participants.

<p>Flow chart of study participants.</p

Factors Associated with Early Mortality in HIV-Positive Men and Women Investigated for Tuberculosis at Ethiopian Health Centers

<div><p>Introduction</p><p>Despite increasing access to antiretroviral treatment (ART) in low-income countries, HIV-related mortality is high, especially in the first months following ART initiation. We aimed to evaluate the impact of TB coinfection on early mortality and to assess gender-specific predictors of mortality in a cohort of Ethiopian adults subjected to intensified casefinding for active TB before starting ART.</p><p>Material and Methods</p><p>Prospectively recruited ART-eligible adults (n = 812, 58.6% female) at five Ethiopian health centers were followed for 6 months. At inclusion sputum culture, Xpert MTB/RIF, and smear microscopy were performed (158/812 [19.5%] had TB). Primary outcome was all-cause mortality. We used multivariate Cox models to identify predictors of mortality.</p><p>Results</p><p>In total, 37/812 (4.6%) participants died, 12 (32.4%) of whom had TB. Karnofsky performance score (KPS) and mid-upper arm circumference (MUAC) were associated with mortality in the whole population. However, the associations were different in men and women. In men, only MUAC remained associated with mortality (adjusted hazard ratio [aHR] 0.71 [95% CI 0.57–0.88]). In women, KPS <80% was associated with mortality (aHR 10.95 [95% CI 2.33–51.49]), as well as presence of cough (aHR 3.98 [95% CI 1.10–14.36]). Cough was also associated with mortality for TB cases (aHR 8.30 [95% CI 1.06–65.14]), but not for non-TB cases.</p><p>Conclusions</p><p>In HIV-positive Ethiopian adults managed at health centers, mortality was associated with reduced performance score and malnutrition, with different distribution with regard to gender and TB coinfection. These robust variables could be used at clinic registration to identify persons at increased risk of early mortality.</p></div